The epitaxial sandwiching technique has been developed to the stage where the development of contrast due to occluded DNA from T.4 Phage using single crystal gold films has been convincingly demonstrated. A computer simulation program has been written and been used to investigate the effect of specimen and diffraction parameters on contrast observed in the electron microscope. The quality of the specimens prepared using existing technology is poor and the final year of this project will be devoted to improving deposition techniques in order to optimize contrast and resolution and minimize the incidence of defects and artifacts. It is hoped to investigate alternative support materials (e.g., platinum) and use biopolymer from other well-characterized sources.